Protein Intake Calculator

Protein is one of the three macronutrients (along with carbohydrates and fats) essential for human health. It is made up of amino acids — the building blocks your body uses to build and repair muscle tissue, produce enzymes and hormones, support immune function, and maintain healthy skin, hair, and nails.

Of the 20 amino acids, 9 are "essential" — meaning your body cannot produce them and must get them from food. Complete protein sources (meat, fish, eggs, dairy, soy) contain all 9 essential amino acids. Incomplete sources (most plant foods) can be combined throughout the day to meet your needs.

This calculator determines your optimal daily protein intake using a weight-based formula adjusted for your fitness goal and activity level:

The protein multiplier is based on guidelines from the International Society of Sports Nutrition (ISSN), American College of Sports Medicine (ACSM), and meta-analyses of protein research:

Research shows that distributing protein evenly across meals optimizes muscle protein synthesis (MPS). The key guidelines:

• 25–40g per meal maximizes MPS per feeding. Going above 40g does not significantly increase muscle building per meal.
• 3–5 meals per day is optimal for muscle protein synthesis. 2 meals per day can work for intermittent fasting, though each meal will contain a larger protein dose with diminishing MPS returns above 40g.
• Post-workout protein (within 2 hours) is important but the "anabolic window" is wider than traditionally believed. Total daily intake matters most.
• Before bed: A slow-digesting protein source (casein, cottage cheese) can support overnight muscle repair.

1. Eating too little protein during weight loss — This leads to muscle loss. When cutting calories, protein needs actually increase (1.6–2.4 g/kg) to preserve lean mass.
2. Loading all protein into one meal — Your body can only use ~25–40g per meal for muscle building. Spreading intake across meals is more effective.
3. Using the RDA as a target — The RDA of 0.8 g/kg is the minimum to prevent deficiency, not optimal for health or fitness. Most active people need significantly more.
4. Ignoring protein quality — Not all protein is equal. Animal and soy proteins are "complete" (contain all essential amino acids). Other plant proteins should be combined for completeness.
5. Worrying about kidney damage — For healthy adults, high-protein diets (up to 2.2 g/kg) have not been shown to cause kidney damage. However, those with pre-existing kidney disease should consult a doctor.